SHORT STATURE AND DELAYED PUBERTY
Parents are often concerned about their
children's growth, especially if they seem to be shorter than
other children that are the same age. While there are many
medical causes for being short and having poor growth, including
growth hormone deficiency, hypothyroidism, Turner syndrome,
inflammatory bowel disease, and kidney problems, most children
who are short are normal. They may have genetic short stature or
a constitutional growth delay.
Children normally grow at a rate of about
23-28 cm/year in early infancy (birth to 12 months) and this
then decreases to about 7.5 - 13 cm/year in later infancy (1 - 3
years). Many children between the ages of 6 and 18 months move
up or down on their growth percentiles, but by 24 months, most
children follow their growth curve and stay on the same
percentile or growth channel.
In early childhood (3 years to puberty) they will then continue
to grow at a rate of about 4.5 to 7 cm/year, up until the time
just before they begin puberty, when their growth will slow to
about 4 cm/year. Growth then accelerates again as they hit their
peak growth velocity in puberty, to about 8-9 cm/year for girls
and 10.3 cm/year for boys. Growth then slows again in girls to
about 7 cm/year after menarche (the first menstrual period)
until they reach their adult height. Boys and girls usually
continue to grow until they are 16-18 years old, but this
depends on when they started puberty.
Among the influences on a child's growth is his overall genetic
potential for growth, which can be determined from his parents'
heights, his nutritional status, and the presence of any chronic
Children with short stature are usually below the 3rd or 5th
percentile on their growth chart for their height. But just as
important as where they are on or below the growth chart is what
their growth velocity or rate of growth has been each year.
Tests commonly performed to evaluate the
growth of a child with short stature include determining a bone
age, which is the chronological age of your child's bones. This
is determined by taking an xray, usually of his left wrist and
hand. If your child's bone age is much less than his
chronological or real age, then there is probably still room for
his bones to grow after the age that you would normally expect
him to already stop growing.
Other tests can include blood tests to
check for hypothyroidism (Free T4 and TSH), growth hormone
levels (usually by checking IGF-1 and IGF BP3 and with an
insulin tolerance test), complete blood counts, blood
chemistries to check for kidney and liver disease), and
sometimes a karyotype to look for chromosomal abnormalities
(especially in girls who may have Turner syndrome).
If the above tests are normal, or if your endocrinologist
doesn't think that testing was even necessary (which is often
the case for many short children), then your child's rate of
growth can just be closely followed every 3-6 months, with a
further evaluation being performed if he does not continue to
have a normal rate of growth.
Another normal condition that can cause short stature is a
constitutional delay in growth. These children, although short,
have a normal growth velocity or rate of growth and will usually
have a delay in starting puberty, and possibly a prolonged
slowdown in growth that is usually present in children just
before they begin puberty. They will usually also have a bone
age that is much less than their chronological age, showing that
there is room to grow and that they will continue growing even
after other children of the same age have stopped growing.
Because of the extra room and time to grow, children with
constitutional delay usually have a normal adult height.
Many parents are worried about growth
hormone deficiency in their short children. Growth hormone is
required for normal growth, and children with growth hormone
deficiency are short, often look younger than their
chronological age, and they can be chubby with their weight
higher than their height. While they will usually have a delay
in their bone age, like children with a constitutional delay,
children with growth hormone deficiency will have a slow rate of
growth and they will have a growth curve that falls away from
the the normal growth curves (unlike other normal causes of
short stature which have a normal rate of growth and a growth
curve that runs parallel to the growth chart).
Treatments for growth hormone deficiency
include growth hormone replacement. This is done by giving daily
injections. Other conditions for which growth hormone is
currently being successfully used include Turner syndrome,
chronic renal failure and Prader-Willi syndrome.
Puberty is said to be delayed when symptoms do not appear by age
13 for girls and age 14 for boys. Delayed puberty can be
hereditary; the late onset of puberty may run in the families.
However, delayed puberty may also be due to chromosomal
abnormalities, genetic disorders, chronic illnesses, or tumors
that damage the pituitary gland or the hypothalamus, which
What are the symptoms of delayed
Indications that a child may be
experiencing delayed puberty is the noted lack of puberty
symptoms. The following are the most common symptoms of delayed
puberty. However, each child may experience symptoms
differently. Symptoms may include:
lack of breast development by age 13
more than five years between breast growth and menstrual period
lack of pubic hair by age 14
failure to menstruate by age 15
lack of testicular enlargement by age 14
lack of pubic hair by age 15
more than five years to complete genital enlargement
How is delayed puberty diagnosed?
In addition to a complete medical history
and physical examination, diagnosis of delayed puberty may
blood tests (to check for
chromosomal abnormalities, measure hormone levels, and test for
diabetes, anemia, and other conditions that may delay puberty)
x-ray - a bone x-ray of the hand or
wrist may be performed to determine bone maturity.
computed tomography scan (Also
called a CT or CAT scan.) - a CT scan shows detailed images of
any part of the body, including the bones, muscles, fat, and
organs. CT scans are more detailed than general x-rays.
magnetic resonance imaging (MRI) -
a diagnostic procedure that uses a combination of large magnets,
radiofrequencies, and a computer to produce detailed images of
organs and structures within the body.
Treatment for delayed puberty depends on the cause of the
problem. Often, when the underlying cause is treated, puberty
proceeds normally. If the delayed puberty is due to heredity, no
treatment is usually necessary. In some cases, treatment may
involve hormone therapy to stimulate the development of
secondary sexual characteristics, or surgery to correct an